Device for feeding material out of silos or from stacks

ABSTRACT

The invention concerns a device for feeding of material from a bottom supporting said material to a central outlet by means of a feed screw performing a wandering movement about the center of the bottom and a rotation about its own axis and in which the driving means for the screw are mounted onto a turning disk mounted in the center of the bottom and surmounted by a protecting casing. The invention intends to prevent the often occurring formation of vaults in the material. To this purpose the casing leaves a portion of the turning disk uncovered and has a feed edge extending downwards towards the disk so as to drive off the material from the outlet opening during rotation of the disk and thereby improve its uniform feed through the outlet opening.

United States Patent Wennberg 5] Mar. 14, 1972 [54] DEVICE FOR FEEDINGMATERIAL OUT OF SILOS OR FROM STACKS [72] Inventor: Olov Carl GustavWennberg, Bjurbacksgatan 8, Karlstad, Sweden 22 Filed: Mar. 5, 1970 [21Appl.No.: 16,654

FOREIGN PATENTS OR APPLICATIONS 1,503,988 10/1967 France ..2l4/l7 DAPrimary Examiner-Robert G. Sheridan Att0rneyYoung & Thompson [57]ABSTRACT The invention concerns a device for feeding of material from abottom supporting said material to a central outlet by means of a feedscrew performing a wandering movement about the center of the bottom anda rotation about its own axis and in which the driving means for thescrew are mounted onto a turning disk mounted in the center of thebottom and surmounted by a protecting casing. The invention intends toprevent the often occurring formation of vaults in the material. To thispurpose the casing leaves a portion of the turning disk uncovered andhas a feed edge extending downwards towards the disk so as to drive offthe material from the outlet opening during rotation of the disk andthereby improve its uniform feed through the outlet opening.

4 Claims, 5 Drawing Figures PATENTEDMAR 14 I972 SHEET 1 [IF 2 FIG. 2

IN V EN TOR.

0401/ (he; 'usmyWsw/msfee I'BY 717M PATENTEDMAR 14 I972 SHEET 2 OF 2INVEN TOR. 040V (he: GMS'TAV/f/E/V/Vdf/GG DEVICE FOR FEEDING MATERIALOUT OF SILOS OR FROM STACKS The present invention concerns a device forfeeding material from a bottom e.g., of a silo or beneath a stack bymeans of a screw and a turning device, which in known manner rotates thescrew about its own axis and simultaneously produces a circularwandering motion of the screw over the bottom, the driving means beingsupported by a turn disk mounted centrally onto the bottom and coveredby a protecting casing. In previously known devices the rotatable screwis mounted on a pinion or a housing placed in the center of an outletopening disposed centrally in the bottom. This arrangement gives oftenrise to the formations of vaults hindering or entirely preventing thefeeding out of the material. This invention intends to obviate thisdisadvantage and to attain such a form of the casing and the turningdisk that an uniform feed of the material without vault formation can beobtained.

The primary characteristics of the invention is that the casing leaves aportion of the turning disk uncovered and forms a feeding edge extendingdown towards the turning disk, said feeding edge upon rotation of thedisk and the casing pushing off the material to facilitate its fallingdown into an outlet opening in the turning disk. The feeding edge can beshaped as a plough wing which because of its shape tends to collect thematerial and to lead it towards the outlet opening in the tuming disk.

A further improvement of the feeding of the material can be obtained, ifthe feeding edge in the center of the casing merges into a vertical wallsituated close to the outlet opening, which wall is traversed by ashaft, on which the screw is mounted. A further improved structure isobtained, if the screw shaft, which extends diametrally through thecasing, is supported both at the periphery of the bottom and at twoplaces between the vertical wall and the periphery of the casing. Theturning disk, which supports the driving means can have a part of themmounted at its underside, while others can be mounted on its upper sideunder protection of the casing. The driving means here concernedcomprise both means to produce the circular wandering motion of thescrew and means to rotate the screw about its axis.

An embodiment of the invention will be described in the following withreference to the accompanying drawings.

FIG. 1 shows a diagrammatic vertical section through the lower part of asilo with the feeding device mounted therein.

FIG. 2 shows a plane view of the device illustrated in FIG. 1.

FIG. 3 shows at an enlarged scale a side view of the screw and drivingmeans, partly in vertical section through the axis of the screw.

FIG. 4 shows a plane view corresponding to FIG. 3.

FIG. 5 shows at a still more enlarged scale the turning disk, the casingand the adjacent end portion of the screw seen as from line 5-5 in FIG.1.

In the drawings, 1 is the lower most often cylindrical-part of a silowall, 2 is a feed screw mounted in the lower part of the silo and 3 isthe bottom of the silo. A turning disk 4 is mounted in a central openingof the bottom, which disk has an outlet opening 5. From this opening thematerial fed towards it by the screw is led through a hopper 6 onto aconveyor 7. The turning disk is peripherally guided by rollers 8 andsupported by rollers 9. An annular guide rail 11 extends within achannel at the outside of the lower end of the silo wall, on which railruns a wheel 12. The wheel 12 is mounted on a shaft which drives thewheel 12 by means of a gear 13 mounted onto the end of the shaft andengaging a fixed circular rack 14, the rotation of the shaft producingthe wandering of the screw over the silo bottom 3. The tubular screw 2,through which the shaft 15 is extending, is mounted onto the shaft bymeans of two bearings 16 and 17. The running wheel 12 is by means of abearing 18 mounted onto the end of the shaft 15 situated near theperiphery of the silo and on the other end of the shaft situated on theturning disk 4 there are two bearings 19 and 20 and a chain wheel 21.This wheel drives shaft 15 by means of a transmission chain 22, a chaingear 23, a worm ear 24 and an electromotor 25 and produces the rotationof e screw 2 so that it wanders over the bottom 3. The screw 2 isrotated by means of a chain wheel 26, a chain 27, a chain gear 28 and aworm gear 29 driven by an electromotor 30.

Some of the driving means above described are mounted onto the undersideof the turning disk 4 and are protected by the latter, while the othersare placed on the upper side of the disk and protected by the casing 31.This casing covers only a portion of the turning disk and leaves anotherportion of it free in front of and behind the outlet opening 5. Behindthe outlet opening the casing is inclined downwards towards the turningdisk and forms a feed down edge in the form of a plough wing 32, whichslightly besides the center of the disk merges into a vertical wall,traversed by the shaft 15 of the screw. Instead of being formed as aplough wing, the edge 32 can extend in a straight line as marked by themixed line 32'.

When the device is working and the screw is wandering around the bottomof she silo simultaneously as it rotates about its own axis, the turningdisk 4 rotates in the direction indicated by the arrow 34. The materialin the silo, which comes into contact with the screw, is fed by ittowards the outlet opening 5. The casing rotating with the turning diskassists in feeding down the material towards the outlet opening andprevents also the forming of vaults in the material, so that an uniformfeed is obtained.

It should be observed that the screw extends from the periphery of thesilo to the turning disk and past its center to the vertical or slightlyinclined wall 33, for which reason it can act on the material in thesilo over the totality of its bottom surface. In order to render thescrew fully effective also near the casing, its threading should extenda little above the top side of the casing.

The driving means for the rotation of the screw about its axis and forits wandering over the bottom of the silo may be located near theperiphery of the silo instead of beneath the turning disk, the casingserving then mainly to improve the feeding down of the material and toprotect the bearings of the screw shaft.

What I claim is:

l. A bottom unloader comprising a screw conveyor, means for swingingsaid screw conveyor in a horizontal path about an upright axis and forrotating said screw conveyor about its own axis to move material towardsaid upright axis, a horizontal disc coaxial with said upright axis andturning with said screw conveyor about said upright axis and having acentral outlet opening, a casing surrnounting a portion only of saiddisc and leaving a portion of said disc exposed, said casing having afeeding down edge that extends downward toward the disc, said dischaving at least a component of its length extending along said screwconveyor in a direction away from said upright axis whereby said edgeduring rotation of the disc and of the casing pushes off material tofacilitate material falling through said outlet opening.

2. An unloader as claimed in claim 1, said feeding down edge having theshape of a plow wing.

3. An unloader as claimed in claim 1, said feeding down edge adjacentthe center of the casing merging into a vertical wall disposed along anedge of said outlet opening and traversed by a central shaft of saidscrew conveyor.

4. An unloader as claimed in claim 1, said means for swinging androtating said screw conveyor being supported by said disc partly on theupper side of said disc and partly on the under side of said disc.

1. A bottom unloader comprising a screw conveyor, means for swingingsaid screw conveyor in a horizontal path about an upright axis and forrotating said screw conveyor about its own axis to move material towardsaid upright axis, a horizontal disc coaxial with said upright axis andturning with said screw conveyor about said upright axis and having acentral outlet opening, a casing surmounting a portion only of said Discand leaving a portion of said disc exposed, said casing having a feedingdown edge that extends downward toward the disc, said edge having atleast a component of its length extending along said screw conveyor in adirection away from said upright axis whereby said edge during rotationof the disc and of the casing pushes off material to facilitate materialfalling through said outlet opening.
 2. An unloader as claimed in claim1, said feeding down edge having the shape of a plow wing.
 3. Anunloader as claimed in claim 1, said feeding down edge adjacent thecenter of the casing merging into a vertical wall disposed along an edgeof said outlet opening and traversed by a central shaft of said screwconveyor.
 4. An unloader as claimed in claim 1, said means for swingingand rotating said screw conveyor being supported by said disc partly onthe upper side of said disc and partly on the under side of said disc.